The Spotter-Truck Positioned System was engineered for those already using spotter trucks to move trailers throughout their site. The SL model series is universally accepted for all trailers. The SL models are easy to use and require only the standard on-board power and pneumatic systems of the spotter truck. The SL can be stored under trailers eliminating the need for storage space. This system is not dependent on wall construction, incline or decline docks, or pooling water at the dock. The SL is a modular platform to which functionality can be easily added. Meets and Exceeds OSHA requirements.